Porthole tube fitting having selfaligned coined fluid seat



Feb. 14, 1961 M. F. BAUER 2,971,780

PORTHOLE TUBE. FITTING HAVING SELF-ALIGNED COINED FLUID SEAT Filed April23, 1959 INVENTOR. MATTHEW F, BAUER AT TORNEYS U ed S a es P t PORTHOLETUBE FITTING HAVING SELF- ALIGNED COINED FLUID SEAT Matthew F. Bauer,16129 Northvale Blvd Cleveland 12, Ohio Filed Apr. 23, 1959, Ser. No.808,434

4 Claims. (Cl. 285-215) major problem resides in the fact that thefitting device swells the threaded porthole and distorts the connectionbody. This swelling of the porthole and the distortion of the body isparticularly objectionable in valve bodies where close clearances mustbe maintained between the valve and the valve body. Faulty valveoperation is the result. In the past, attempts have been made toeliminate the swelling of the porthole when the fitting is turnedthereinto by the use of O-rings or other sealing gaskets such as shownin Patent No. 2,342,425, issued February 22, 1944. These types offittings in the trade are generally referred to as straight threadO-ring bosses, or simple, O-ring boss mountings. As is well known in thetrade, these O-ring boss mountings are not completely satisfactorybecause they readily become damaged in high pressure operation,resulting in leakage.

An object of the present invention is to make a fluid connection betweena connection body and a fitting device with a metal-to-metal seal and atthe same time prevent swelling of the porthole when the fitting isturned thereinto.

Another object of the invention is the'provision of a fluid connectionhaving a metal-to-metal seal which is self-aligning regardless of anymisalignment between the fitting device and the connection body.

Another object of the invention is the provision of a fluid sealconnection which makes its own seat as the fitting device is turned intothe porthole of the connection body.

Another object of the invention is the provision of coining a fluid seatin a substantially sharp corner around a circular opening by pressing asubstantially conical body thereagainst with the force applied to theconical body at a place which is substantially in longitudinal alignmentwith said fluid seat being coined.

Another object of the invention is the provision of coining a fluid seatin a substantially sharp corner around a circular opening by pressing asubstantially conical body thereagainst with a sleeve nut surrounding ashank attached to the conical body, whereby the sleeve nut engages ashoulder on the back side of the conical body at a place which issubstantially in longitudinal alignment with said fluid seat beingcoined. Y

Another object of the invention is a safety design provision whichprevents overtightening or overswedging of the metal-to-metal sealingsurface, thereby affording a positive control against the swelling ofthe porthole.

Another object of the invention is the provision of a shallow portholewhich has a depth less than the diameter thereof.

Another object is the provision of supporting the minimum dimensionportion of the conical seating surface by aninwardly extending annularledge which is responsive to fluid pressures to give a fluid pressureseal.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims taken in conjunctionwith the accompanying drawing, in which:

Figure l is an enlarged and side elevational view of a fluid sealconnection embodying the features ofthe invention with certain portionsshown in cross-section to better illustrate the invention;

Figure 2 is an end view of the fitting device shown in Figure 1 lookingfrom right to left, with the dash-dot lines in Figure 2 showing themanner in which the elbow fitting device maybe swiveled to anyparticular direction to accommodate the tubing which is to be anchoredthereto;

Figure 3 is a side view of a straight fitting device having portionsbroken away to illustrate the cross-section of the outline of thefitting device;

Figure 4 is an enlarged fragmentary view of Figure 1 showing the fittingdevice turned in the porthole finger tight;

Figure 5 is a fragmentary view similar to Figure 4 showing the fittingdevice turned into the porthole with a minimum torque value;

Figure 6 is a fragmentary view similar to Figure 4 showing the fittingdevice turned into the porthole with an intermediate torque value;

Figure 7 is a fragmentary view similar to Figure 4 showing the fittingdevice turned into the porthole with a maximum safe torque value; and

Figure 8 shows the self-aligned conical sealing surface when there ismisalignment between the fitting device and the connection body as isoften the case through imperfect machining operations.

-The reference character 10 represents a connection body which may be aportion of a valve, a pump or a cylinder into which a fitting device 11is threadably and sealingly connected. The connection body has anoutside surface 38 and an inside surface 39 and has a first innercylindrical wall 12 having female threads 14 there in and constituting aporthole to receive the fitting device 11. Disposed axially inwardly ofthe first inner cylindrical Wall is a second inner cylindrical wall 13constituting a fluid passageway in the connection body. The first andsecond cylindrical walls 12 and 13 have axes substantially in alignmentwith each other, although due to machining the axes may not be perfectlyin alignment with each other. The first cylindrical wall 12 has a largerdiameter than the second cylindrical wall 13 and terminates in atransversely extending abutment wall 15 which is preferably disposedsubstantially perpendicularly to the axes of the cylindrical walls. Theabutment Wall 15 and the second cylindrical wall 13 meet with each otherto define a substantially right-angle sharp annular corner 16. In actualpractice, elaborate machining operations have been set up for makingO-ring porthole bosses. With this invention, there is no need forelaborate machining operations to insure perfect sealing. In fact, withthe present invention, a perfect seal is assured even though the axes ofthe first cylindrical wall and the secondcylindrical Wall may bemisaligned or eccentric with respect to each other. Furthermore, aperfect seal may be effected with 1 tion body. The entire machiningoperation for the present invention may be performed without specialtools and with a minimum of attention.

The fitting device 11 which is illustrated, is of the Tor elbow type.andcomprisesa hollow body .18 having an upper side 19 and a left-handside 20. Extending from the supper side 19 is a .hollow arm 21to which.a tube 22 may be connected byrne'ans ofa sleeve 24 and a nut 23.Theconstruction of the tube, and the sleeve and nut may be of any Wellknown type and maybe either of the flare type of construction, thenoflare type ofconstruction .or the self-flare type of constructionwhich is now available on the market. Extending from the left-hand side20 of the hollow body 18 is a hollow arm 26 which is adapted to beconnected to the construction body 10. As illustrated, the hollowarm 26comprises an.inter mediate shank portion 30 having ,on therightrhan'dnend thereof male threads 27 and having -.on the left-handend thereof a sealing head .or sealing .end portion 29. The male threads27' are adapted to-threadably engage female threads 23 provided in thehollow body 18. .In order to make a good fluid seal the right-hand end.of the shank portion 36 is provided with aconical .or inclined abuttingsurface 37 which presses against an inclined shoulder 36 onthe hollowbody 18.

The sealing head or end portion 29 is provided with an external conicalsealing surface 31, flaring from a minimum diameter to a maximumdiameter in a direction toward the outside surface 38 at an anglepreferably between fifteen and seventy-five degrees with respect to theaxes of the fitting orcylindrical walls. Specifically, the angle of theflare is preferably forty-five degrees or thirty-seven and one-halfdegrees depending upon the material and fluid pressures. The conicalsealing surface 31 and said transversely extending abutment 15preferably have an angle therebetween which lies in a range betweenfifteen degrees and one-hundred and twenty degrees. The transverselyextending abutment wall 15, instead of being substantially perpendicularto the axes of the fitting as shown in the drawings, may comprise aninverted cone, in which case the angle between the conical sealingsurface 31 and the transversely extending abutment may be at leastone-hundred and twenty degrees. 7 V

The conical sealing surface 31 at its minimum diameter has a dimensionless than the diameter of the second cylindrical wall 13 and extendsaxially thereinto; The conical sealing surface 31 at its maximumdiameter has a dimension greater than the diameter of the secondcylindrical wall 13 and is spaced in an axial direction from and facesthe abutment end wall 15.

The approximate width of the abutment end wall 15 is preferably asfollows for the respective tube sizes: tube, .051 inch; tube, .085 inch;/s" tube,';085 inch; /2" tube, .062 inch; A5" tube, .051 inch; tube,.086 inch; 4;" tube .094 inch;'1" tube, .094 inch; 1% tube, .117 inch;and 1 /2" tube, .117 inch.

A threaded sleeve nut 33' having male threads 34 thereon surrounds theintermediate shank portion 30. The left-hand end of the threadedsleeve-nut .33 is provided with an'abuttable nut end 35 which pressedagainst a shank shoulder 32 on the sealing end portion or. head 29,whereby when the threaded sleeve nut 33 is turned into the connectionbody a tight fluid seal is made between the conical sealing surface 31and the sharp corner 16 of the connection body 10. V

In manufacture,-the threaded'sleeve nut 33 is inserted over theintermediate shank portion 30 preparatory to threadably turning the malethreads27 into thefemale threads 28 of the hollow body 18. In order toinsure a fluid tight seal between the .shank portion 3.0 and the hollowbody 18, the male and female threads 27' and 28 as well as the othermating surfaces are preferably brazed by furnace or other temperatureoperation. The brazing of the mating surface s,including the male andfemale threads 27 and 28,.and. the. inclined shoulder 36 '4 and theinclined abutting surface 37 insures a good fluid tight joint which isnot subject to leakage.

The conical sealing surface 31 is harder than the sharp annular corner16 and may be made harder by the selection of materials, by casehardening or by heat treatment. The conical length of the conicalsealing surface 31 is greater than one pitch length of the male andfemale threads 14 and 34. When pressed against the sharp annular corner16, the hard conical sealing surface 31 forms thereon a flat conicalseating surface or fluid seat 25 which perfectly matches the conicalsealing surface 31 regardless of any misalignment between the fittingdevice 11 and the connection-body 10.

The pressing engagement between the abuttable nut end 35 of the sleevenut33 and the shank shoulder 32 may be referred to as an annular nutshoulder engagement. The diameter of the inner cylindrical wall 13 andthe shank 30- arepreferably about the same. These diameters for therespective size of tube fittings, maybe approximately as follows: tubeV32 inch; 7 6 tube, inch; /8" tube, inch; /2 tube, W inch; tube, inch, 4tube, inch; /8 tube, inch; 1" tube, 1% inch; 1 /4" tube; 1 inch; and 1/2" tube, 1%; inch.

Accordingly, the force for coining the sealing surface or fluid seat 25by pressing the conical sealing surface 31 against the sharp corner 16is substantially in longitudinal alignment with the fluid seat 25 beingcoined. Thus, there are no forces tending to collapse the conicalsealing head, because'thenut-shoulder engagement is substantially inlongitudinal alignment with the fluid seat 25. being coined. That is tosay, the maximum diameter of the coined fluid seat 25 is intermediatethe radial width of the nut-shoulder engagement. The coining operationcompacts the metal at the corner and increases the density of the metalat the fluid seat 25 to make a good sealing connection. The flattenedconical seating surface or fluid seat 25 preferably has a maximum widthless than one pitch length of the male and female threads 34 and 14. Theminimum width preferably isnot less than one-fourth of the pitch lengthof the threads. The male and female threads 34 and 14 are preferablymachine threads and not pipe threads.

In practice for a A" tube 22 themachine threads are preferably Ae20 (theindicating the outside diameter of the machine threads and the 20 beingthe number of threads per inch); for a 7 tube, the machine threads are/220; for a /8" tube, the machine threads are l8; for a /2" tube, themachine threads are %-16; for a /8" tube, the machine threads are 'Vs14;for a tube, the machine threads are 1 l2; for a 'Z s" tube, the machinethreads are l% .12; for a 1" tube, the machine threads are 1 l2; for a1%" tube, the machine threads are 1%-12;.f0r a 1 /2" tube, the machinethreads are 1%12.

Accordingly, the lower and upper ranges of the width of the flattenedconical seating surface 25 for the respective tube sizes .wouldpreferably be asfollows: A" tube, .0125-.050 inch; 7 tube, 0125-050inch; tube, .0l4-.055 inch; /2" tube, .015.0625 inch; tube, .017.070inch; 4" tube, .020..083 inch; /s.'.' tube, .O20-.083 inch; 1" tube,.020.083 inch; 1 /4" tube, .020-083 inch; and 1 /2 tube, .020.083 inch.

In this invention, the male threads 34 preferably make not more thanfive full thread engagements with thefemale threads 14. In the drawing,a four-thread engagement is shown. Thus, if an attempt ismade to turnthe fitting device brutally tight into the conection body, the threadsmay tend to strip or give before the conical seal-- ing surface 31swedges or-swells the boss to deform and damage the connection body. Thesharp annular corner 16 is disposed inwardly of-theconnection body 10from the outside surface 38 fordistance less than the outside Figure 5shows the machine threads turned with a minimum torque value. Under thissituation the sharp annular corner 16 is flattened a minimum amount tomake a metal-to-metal seal. In Figure 6, the machine threads are turnedto an intermediate torque value in which case the sharp annular corner16 is flattened an intermediate amount. In Figure 7, the machine threadsare turned with a maximum of safe torque and the sharp annular corner 16is flattened a maximum safe amount. The extent to which the sharpannular corner 16 may be flattened is preferably no greater than onepitch length of the machine threads 14 and 34. In practice, the sealeffected by flattening the sharp annular corner 16 as shown in Figures5, 6 and 7 will make a good fluid seal. In turning the sleeve nut 33into the connection body, the operator senses a feeling that the conicalsealing surface 31 is flattening the sharp annular corner 16 and giveshim a cush oning indication that a good seal is being effected. Thus,the operator will stop turning the nut when he feels the cushioningturning becoming tighter. After the machine threads have been turnedfinger tight, it is only necessary for the operator to turn the sleevenut 33 less than one full turn because, if an attempt is made to turnthe sleeve nut more than one full turn, the operator will instinctivelystop turning the nut, being a safety feature. By reducing the number offull thread engagements to five or less, the location of the abutmentend wall 15 may be substantially midway between the inside and outsidesurfaces 38 and 39 of the wall of the connection body 10. The threads 14and 34 are preferably straight, but may be pipe threads with wide threadtolerance to insure proper coining operation. The sharp annular corner16 which is to be flattened is located not more than one-half thethickness of the wall of the connection body 10 from the outside surface38, where maximum resistance to swedging is present. Ordinarily, aclearance of substantially .001 or .004 of an inch' clearance isprovided between the machine threads 14 and 34. A clearance ofsubstantially .001 to .01G of an inch may be provided between thesleeveinut 34 and the intermediate shank 30. Therefore, a small amountof clearance or leeway is provided for allowing the conical sealingsurface 31 to self-align itself with the flattened seating surface 25 tomake a perfect metalto-metal seal. The Figure 8 shows the flattenedseating surface 25 as being eccentric as would be the case if thefitting device were not perfectly in alignment with the connection body.Furthermore, the abutment end Wall 15 may have a chattered machinefinish and yet the metal-to-metal seal effected in the present inventionholds high fluid pressure.

Just prior to the time that the threaded sleeve nut 33 is finally turnedto its maximum safe torque value, the fitting may be swiveled or turnedto any position for connection with the tube 22, see Figure 2 as anillustration as to how a swivel tube fitting may be swiveled toaccommodate a connection for a tube.

The Figure 3 shows a straight type fitting 4-1 which is provided with aconical sealing surface 42. This fitting may be threadably screwed intothe machine thread 14 of the connection body and the conical sealingsurface 42 will make a metal-to-metal seal as it flattens the sharpannular corner 16 into the conical seating surface 25. The male threads43 are preferably machine threads and are of the same dimension as themachine threads 6 34 on the sleeve nut 33. The" straight fitting, asshown in Figure 3, does not need a swivel and may be threadablyconnected directly to the connection body 10. The present inventionenables the thread to be machine threads for both the straight fittingas shown in Figure 3 as well as the swivel fitting as shown in Figures 1and 2 0f the elbow and T type,

The coining operation causes the metal of the sharp corner to flowprincipally in an axial direction in the porthole and forms a radiallyinwardly extending annular ledge 40 at the minimum dimension of theflattened fluid seat (see Figures 5, 6 and 7). The annular ledge 40 inactual practice may extend inwardly of the cylindrical wall 13 for adistance of approximately .005 to .030 of an inch. Under fluidoperatiomhigh fluid pressures tend to press the annular ledge 40 tightlyagainst the conical sealing surface 31 of the head 29 to provide a fluidpressure seal. In other words, the conical seating surface 25 at itsminimum dimensionis supported by an annular ledge 40 extending inwardlyfrom the cylindrical wall 13 whereby the fluid presses the inwardlyextending annular ledge against the conical sealing surface 31 toprovide a fluid pressure seal.

The terms substantially conical sealing surface and substantiallyconical seating surface may include constructions other than a true coneso long as substantiallythe same results are obtained. The cone surfacemay be somewhat concave or convexed.

Although this invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and the scope of the invention as hereinafterclaimed.

What is claimed is:

1. A coined metal-to-metal porthole fluid sealing connection comprising,a connection body, a fitting device threadably and sealingly connectedto said body, said connection body having an outer surface and aporthole extending inwardly from said outer surface, said portholedefined by a porthole wall having female threads thereon,

said porthole wall terminating in a transversely extending substantiallynon-expandible abutment wall, said connection body having a fluidpassageway defined by an annular wall meeting with said abutment walland defining an annular corner therewith, said annular wall at saidannular corner having an initial predetermined diameter, said fittingdevice having a shank portion with a sealing head portion fixedly andsealingly secured thereto and mounted in said porthole, said shankportion having a fluid passageway therein communicating with said fluidpassageway in said connection body, said sealing head portion having ona rearward side thereof a shank shoulder and having on a forward sidethereof a substantially conical sealing surface engaging said annularcorner and flaring from a minimum diameter less than said initialpredetermined diameter to a maximum diameter in a direction toward saidouter surface, said substantially conical sealing surface being harderthan said annular corner, a sleeve nut surrounding said shank portionand having a nut end abuttable against said shank shoulder, said nut endand said shank shoulder making an annular nut shoulder engagement, saidsleeve nut having male threads thereon to threadabl-y engage said femalethreads on said porthole wall for forcing said substantially conicalsealing surface against said annular corner to substantially conicallydeform and thereby coin said annular corner into a self-alignedsubstantially conical seating surface which self-matches saidsubstantially conical sealing surface, said substantially conicalseating surface having a coined minimum diameter less than said initialpredetermined diameter of said annular wall at said annular corner, saidannular wall at .7 said minimum diameter being deformed and, comprisingan annular ledge extending inwardly from :said initial predetermineddiameter.

2.,A coined metal-to-metal porthole fluid sealing connection comprising,a connection body, -a' fitting device threadably and sealingly connectedto said body, said connection body having an outer surface'and aporthole extending inwardly from said outer surface, said portholedefined by a porthole wall having female threads thereon, said portholewall terminating in a transversely extending substantiallynon-expandible abutment wall, :said connection body having a fluidpassageway defined by an annular wall meeting with said abutment walland defining an annular corner therewith, said annular wall at saidannular corner having an initial predetermined diameter, said ,fittingdevice having a shank portion with a sealing head portion fixedly andsealingly secured thereto and mounted .in said porthole, said shankportion having a fluid passageway therein communicating with said fluidpassageway in said connection body, said sealing head portion having ona rearward side thereof a shank shoulder and having on a forward sidethereof a substantially conical sealing surface engaging said annularcorner and'flaring from ta minimum diameter less than saidinitialpredetermined diameter to a maximum diameter in a directiontoward said outer surface at an angle which lies between fifteen andseventy-five degrees with respect to the axis of said porthole wall,said substantially conical sealing surface and said transverselyextending abutment wall having an angle therebetween lying in a rangebetween fifteen degrees and one-hundred and twenty degrees, saidsubstantially conical sealing surface being harder than said annularcorner, a sleeve nut surrounding said shank portion and having .a nutend abuttable against said shank shoulder, said nut end and said shankshoulder making an annular nut shoulder engagement, said sleeve nuthaving male threads thereon to threadably engage said female threads onsaid porthole wall for forcing said substantially ,conical sealingsurface against said annular corner to substantially conically deformand thereby coin said annular corner into a self-aligned substantiallyconical seating surface which self-matches said substantially conicalsealing surface.

3. A coined metal-to-metal porthole fluid sealing connection comprising,a connection body, a fitting device threadably and sealingly connectedto said body, said connection body having an outer surface and aportholeextending inwardly from said outer surface, said porthole defined by aporthole wallhaving female threads thereon, said porthole wallterminating in a transversely extending substantially non-expandibleabutment wall, said connection body having a fluid passageway defined byan annular wall meeting with said abutment wall and defining an annularcorner therewith, said annular wall .at said annular corner having aninitial predetermined diameter, said fitting device having'a shankportion with a sealing head portion fixedly and sealinglysecured theretoand mounted in said porthole, said shank portion having a fluidpassageway therein communicating with said fluid passageway in saidconnection body, said sealing head portion having on a rearward sidethereof a shank shoulder and having on a forward side thereof a substantiaily conical sealing surface engaging said annular corner ,and flaringfrom a minimum diameter less than said initial diameter to a maximumdiameter in a direction toward said outer surface at an angle which liesbetween fifteen and seventy-five degrees with respect to the axis ofsaid porthole wall, said substantially conical sealing surface and saidtransversely extending abutment wall having an angle therebetween lyingin a range between fifteen degrees and one-hundred and twenty degrees,said substantially conical sealing surface being harder than saidannular corner, a sleeve nut surrounding said shank portion and havinganut end abuttable .against said shank shoulder, said nut end andsaidshank shoulder making an annular nut shoulder engagemenusaid sleevenut having male threads thereon to :threadably engage said female:threads on said porthole wall for forcing'said substantially conicalsealing surface against said annular corner to substantially conicallydeform and thereby coin said annular corner into a self-alignedsubstantially conical seating surface which self-matches saidsubstantially conical sealing surface, said substantially conicalseating surface having a width lying approximately between onefourth toone-pitch length of said threads, said abutment wall disposed inwardlyof said connection body from said outer surface for a distance less thanthe outside diameter of said female threads, said ,male threads makingnot more than five full thread engagement with said female threads.

4. A coined metalto-metal porthole fluid sealing con- .nectioncomprising, a connection body, a fitting device threadably and sealinglyconnected to said body, said connection body having an outer surface anda porthole extending inwardly. from said outer surface, said portholedefined by a porthole wall having female threads thereon, said portholewall terminating in a transversely extending substantiallynon-expandible abutment wall, said .connection body having a fluidpassageway defined by an annular wall meeting with said abutment walland defining an annular corner therewith, said annular wall at saidannular corner having an initial predetermined diameter, said fittingdevice having a shank portion with :a sealing head portion fixedly andsealingly secured thereto and mounted in said porthole, said shankportion having a fluid passageway therein communicating with said fluidpassageway in said connection body, said sealing head portion having onarearward side thereof a shank shoulder and having on a forward sidethereof a substantially conical sealing surface engaging said annularcorner and flaring from a minimum diameter less than said initialpredetermined diameter to a maximum diameter in a direction toward saidouter surface, said substantially conical sealing surface being harderthan said annular corner, a sleeve nut surrounding said shank portionand having a nut end abuttable against said shank shoulder, said nut endand said shank shoulder making an annular nut shoulder engagement, saidsleeve nut having male threads thereon to threadably engage said femalethreads on said porthole wall for forcing said substantially conicalsealing surface against said annular corner to substantially conicallydeform and thereby coin said annular corner into a self-alignedsubstantially conical seating surface which self-matches saidsubstantially conical sealing surface, said substantially conicalseating surface having a coined minimum diameter less than said initialpredetermined diameter of said annular wall at said annular corner, saidannular wall at said minimum diameter being deformed and comprising anannular ledge extending inwardly from said initial predetermineddiameter, said substantially conical seating surface having a widthlying approximately between one-fourth to one-pitch length of saidthreads, said abutment wall disposed inwardly of said connection bodyfrom said outer surface for a distance less than the outside diameter ofsaid female threads, said male threads making not more than five fullthread engagement with said female threads.

References Cited in the file of this patent UNITED STATES PATENTS

